20 SUB-ALPINE PLANTS 



big boulders. S. cuneifoUa is particularly useful for quickly covering 

 up rocks and ugly banks with its great tangled mass of pretty 

 foliage. 



Most of tlie ' encrusted ' section will benefit by top-dressing with 

 giitty loam in early autumn. Some should be wedged tightly 

 between stones ; and in dealing with small kinds, such as casia, 

 diapensoides, Burseriana, etc., care should be taken that they do 

 not get washed out of their place in winter. The small rosettes of 

 encrusted Saxifrages may be transplanted at any time, and it 

 strengthens the flowering shoot if the offshoots are removed. 

 They may be planted in ordinary pots filled with sandy loam. 

 S. longifoKa may be placed between a couple of more or less upright 

 rocks, so that water cannot collect in the large rosettes. It takes 

 two or three years to come to maturity, and after flowering and 

 seeding it dies. S. florulenia is another handsome species to be 

 treated in the same way, but it prefers a vertical position, and 

 has a still greater hatred of surface moisture. It should, however, 

 have plenty of moisture in the soil. 



Grit is beneficial to most of the Saxifrages because it checks the 

 evaporation of moisture in summer, and prevents damp from 

 stagnating round the collar of plants in winter. The reason why 

 roots are often found in a network ovei* the surface of a stone is 

 because stones in the soil remain cool and moist, even in summer. 

 It is therefore well to mix a quantity of stone chips with ordinary 

 loam when making a rockery. They tend to keep the soil open and 

 porous rather than sodden and water-logged. The air can penetrate 

 further, and frost exercises its pulverising influence on a broken, 

 gritty soil better than on a dense, compact one. 



Saxifrages of the ofpositifolia group die away in two or three 

 years and should be taken up and pulled to pieces in fresh soil, 

 and grit and leaf-mould may be worked into the shoots as a top- 

 dressing. 



Though in the wild state many Saxifrages grow almost solely on 

 limestone, and a few seem to thrive only on granitic rocks, it has 

 been found in cultivation that they are not so particular, and the 

 great majority will live in an ordinary loamy soil, especially if it 

 contains a fair proportion of lime. 



In my former volume ^ I did not sufficiently emphasise the fact 

 that in the Alps themselves certain plants avoid calcareous soil in 

 some districts, while they tolerate it in others ; and in a few cases 

 I was tempted to generalise about them in a manner which further 

 observations and reading have proved unwise. For example, 

 one of my kindest critics points out that the common Ling (Calluna 

 vulgaris) is not strictly speaking a lime hater, for it is fairly common 

 on the hillsides of the Dolomites, where it grows mixed with 

 Erica carnea, which almost always affects limestone soils. Then 



' Alpine Plants of Europe, p. 5. 



